It is an unfortunate fact that many women contract breast cancer and must have the affected breast removed. After removal of one or both breasts, most mastectomy patients in today's society seek a prosthetic replacement to feel whole, and present a normal appearance beneath clothing. Another goal of breast prostheses is to reduce stress on the spine by maintaining the body's natural balance. Early fabric prostheses were never very satisfactory, and surgically implanted prostheses are expensive and involve health risks. Therefore, external silicone breast prostheses have become extremely popular with mastectomy patients.
The first external silicone breast prostheses included a single volume of a two-component cross-linked silicone material contained within a cavity formed by two pieces of polyurethane film. The silicone material is cured in a mold that determines the shape of the prosthesis. Such prostheses were designed to be worn inside a brassiere. An example of such a prosthesis and a mold are described in U.S. Pat. Nos. 4,172,298 and 4,247,351 to Rechenberg.
Eventually, prosthesis designers determined that certain advantages could be obtained by forming a prosthesis from two volumes of silicone materials that have different degrees of softness. Such prostheses include three pieces of polyurethane film, which are welded together along a common peripheral edge to form front and rear chambers. In some products, the firmer silicone material is in the front chamber. In others, the firmer silicone material is in the rear chamber.
U.S. Pat. No. 4,950,291 to Mulligan describes a two-chamber prosthesis in which the front chamber is relatively thin. The silicone material in the larger rear chamber, which is placed next to the chest wall, is softer than that in the front chamber. The softer silicone material conforms to the shape of the chest wall and moves with the body, thereby providing a natural appearance. The softer silicone material helps redistribute the weight of the prosthesis across and against the chest wall and away from the brassiere shoulder strap, which reduces stress on the shoulder. The firmer silicone material in the front chamber supports the soft rear chamber, prevents the prosthesis from collapsing, and gives shape to the product.
As mentioned above, other two-chamber prostheses place the firmer silicone material in the rear chamber. An example of a two-chamber prosthesis of this type is sold by the assignee of the present invention under the trademark "DELTA PERSONALLY." In this prosthesis, the rear chamber, which contains the firmer silicone material, is relatively thin. The larger front chamber contains the softer silicone material. This configuration is advantageous because the firmer rear chamber simulates the pectoralis chest muscles while the softer front chamber moves like a natural breast. This prosthesis provides a significant natural drape with softness to fill and mold to a brassiere cup completely and naturally. The overall softness of the prosthesis helps the prosthesis mold to the chest wall and helps redistribute the weight of the prosthesis across and against the chest wall and away from the brassiere shoulder strap.
Subsequent developments led to the introduction of attachable prostheses, which could be attached to the skin of the wearer. Like the earlier silicone prostheses, the attachable products included a single volume of a two-component cross-linked silicone material contained within a cavity formed by two pieces of polyurethane film. The prosthesis is held in place on the wearer's chest by a skin support or fastening slab, which has a skin-friendly adhesive on one side and an attachment members on the other side. The prosthesis is attached to the skin support by complementary attachment members. U.S. Pat. No. 5,071,433 to Naestoft et al. and U.S. Pat. No. 5,352,307 to Wild describe attachable prostheses that employ hook-and-loop fasteners, where the hook material is on the prosthesis and the loop material forms one side of the skin support.
Although it may appear to be a simple matter to combine the attachment members of the Naestoft patent with the two-chamber prostheses described above, the simple combination of these features leads to unsatisfactory results. In the case of the soft back two-chamber prosthesis, the back chamber is too soft to support the weight of the prosthesis. In the case of the soft front two-chamber prosthesis, the soft front tends to droop under the weight of the prosthesis and cause the top portion of the prosthesis to pull away from the wearer' skin. Although this may be remedied to some degree by moving the attachment members up along the top edge of the prosthesis, this results in positioning of the skin support that is unacceptable for two reasons. First, the skin support must be positioned so close to the edge of prosthesis that it may be visible around the edges of the prosthesis. Second, this configuration tends to suspend most of the weight of the prosthesis from the top of the skin support, which tends to peel the skin support away from the wearer's skin.
Therefore, there is a need in the art for an attachable, two-chamber prosthesis. An attachable two-chamber prosthesis should provide an acceptable fit and transition to the wearer's chest. Furthermore, an attachable two-chamber prostheses must allow the skin support to be adequately concealed beneath the prostheses and minimize the tendency to peel the skin support away from the wearer's skin.